Over the years, neuropathologic characterization of autopsy-derived brain tissues has occupied a central position in research on amyotrophic lateral sclerosis-parkinsonism dementia complex of Guam. Within this Program, the Neuropathology-Brain Bank core (core C) will continue to receive brain specimens (both fixed and frozen) from the Clinical core (core B) on Guam. These brain specimens will be derived from three sources, a) cases showing clinical evidence of age-related neurodegeneration who have been identified and followed by the Clinical core, b) deceased members of a large cohort of elderly Chamorros (age 65 or above) who have been identified and longitudinally assessed for neurologic and cognitive function (see subproject by Galasko) and c) specimens that were obtained in conjunction with prior research studies on Guam in order to construct a brain tissue repository that is more fully representative of all forms of neurodegenerative disease on Guam as well as include additional examples of specimens derived from patient who died in the earlier phases of the disease outbreak. The core will 1) provide supervision and advice to the Clinical core (core B) to enable the Program to obtain optimally fixed and preserved autopsy-derived brain specimens with a minimum amount of postmortem delay 2) carry out MRI examinations on all fixed brain specimens, 3) perform dissection, preservation and storage of received brain specimens and distribute appropriate tissue samples to investigators within the Program, 4) perform complete neuropathologic evaluation and diagnosis of each brain specimen, 5) determine the extent and distribution of relevant neuropathologic lesions in these specimens, 6) incorporate these data above in the neuropathology database, 7) obtain Guam-derived brain specimens obtained in conjunction with prior NINCDS registry studies that were evaluated neuropathologically and are being stored in the Brain Research Institute, Niigata, Japan, and 8) retain in a preserved state brain samples obtained in conjunction with the above and serve as a national/international brain bank repository to make available appropriate brain tissue specimens to qualified researchers.